dad's libby is dead in the driveway. sorta. sometimes it starts, sometimes nothing happens when you turn the key (radio and lights all work). I read in another thread about slamming the shifter all the way back and all the way forward and that seemed to work. or it was coincidence. either way, I didn't find a cure for the condition in my searches if indeed it was the sensor that detects shifter position is bad. thoughts?

Intermittent non-start can be a bad battery, bad ignition switch not to be confused with the key switch, or a failure of the start system to recognize that the transmission is in park or neutral. I have personal experience with a virtually brand new battery failure (intermittent short between cells - not on CRD) causing random start/no start. Either have the battery load tested or better yet if you have access to a known good battery you can drop it in on a temp basis and see if the problem goes away. See viewtopic.php?f=5&t=60575&hilit=ignition+switch for a similar problem that turned out to be the ignition switch (see the last post for the part); apparently on modern (aren't they wonderful) car systems turning the key doesn't send current directly to the starter it sends current to a separate switch that then "asks" the ECU for permission to start the vehicle hence if that switch goes bad the ECU gets no "can I please start" signal. The same string has a brief discussion about the transmission issue but I'm not sure what system Jeep uses to indicate the transmission is in park or neutral. On older vehicles it was often a switch keyed to the gear shift lever postion which could occassionally stick and cause random start/no start.

There are other potential causes but this is where I'd start looking particularly if the starter is not getting power.

PS if there is a ground cable for the starter be sure it's completing the ground circuit.

My brother had the same problem on 2006 CRD. Problem was bad ignition starter switch ( AIRTEX / WELLS Part # 1S5932) and bad ignition switch actuator pin ( DORMAN Part # 924704 at http://www.rockauto.com - 50Us$ both). You can try to bypass ignition switch relay in PDC (black plastic box under the hood with fuses and relays) and if jeep start cranking, problem is in switch or pin. If no crank then check what papaindigo said.

Pull the shield off the top of the gear shifter, there are 2 small cables in there. IIRC, the passenger-side one is the sensor cable, it is not electrical, its an aircraft wire and the sensor is actually located under the steering wheel. Unhooked, problem solved permanently.

_________________Proud supporting vendor of LOST JeepsProvider of high quality CRD service in your driveway. Need help? Just ask! I've taken it apart more than most. Email (button below) is preferred to PMOver 70 CRDs currently driving with my timing belt, rockers, or ARP Studs.Just remember: Bad noises = REALLY bad things.

My brother had the same problem on 2006 CRD. Problem was bad ignition starter switch ( AIRTEX / WELLS Part # 1S5932) and bad ignition switch actuator pin ( DORMAN Part # 924704 at http://www.rockauto.com - 50Us$ both). You can try to bypass ignition switch relay in PDC (black plastic box under the hood with fuses and relays) and if jeep start cranking, problem is in switch or pin. If no crank then check what papaindigo said.

Good information to slip into the Owner's Manual, or mark on the PDC, if your memory is as bad as mine.

Good points made, let me add a little.When I had intermittent electrical problems brought into the repair shop I owned years ago. I made up a tool that had long leads with alligator clips. Inside the box were LEDs that had 1K resistors to drop the voltage. I put a black alligator clip cover on the Cathode (- short end) of the LED ( use Cathy to remember) and the red on the (+ long end) Anode end (Andy to remember). Since the Cathode lead was shorter, I soldered the 1K resistor to the Cathode lead. Then we would hook up the Alligator clips to the circuits to monitor them as we drove the car on errands. The tech would come back saying it was the XXX, then we fixed it. For anyone that can't make the Cathy-Andy connection, send a PM, we don't want the moderators to get upset.

I thought of a quick way to test the actuator cable without pulling anything apart on the shifter console - With the engine off and in park, pull back slightly on the shifter to apply tension, and try cranking the engine.

If it doesn't go... The cable is the culprit b/c the tolerance (and how much it moves normally) isn't much. The cable is pushed toward the front of the vehicle when the selector is in park, and just shifts backwards slightly when the selector is anywhere else. All you need to do is unclip the end of the cable, and push the end into the sheath until it stops (about 1/4") and tuck it away in there.

This won't affect anything else in the operation of your CRD, the shift interlock (that foot-on-brake-to-shift) idiot switch will still be there and functioning... Unless that 2-wire connector happens to "fall out" like it did on mine. Strange how that happens sometimes.

_________________Proud supporting vendor of LOST JeepsProvider of high quality CRD service in your driveway. Need help? Just ask! I've taken it apart more than most. Email (button below) is preferred to PMOver 70 CRDs currently driving with my timing belt, rockers, or ARP Studs.Just remember: Bad noises = REALLY bad things.

looks like it's acting up again. unfortunately I'm back in michigan so I have to diagnose through the phone. he says that in the past week he occasionally needed to push harder on the key to get it to start. now it won't start at all. so tomorrow I'll be trying to talk him through some of the diagnosing procedures.

a'ite. dad says it definitely has to do with the heat of the day. in the morning and evening it starts fine, but it the hot afternoon it won't. oh, and swapping the starter relay for a different one did nothing.

In the heat of the south? That battery is WAY beyond its service life, and when an Optima dies, this is exactly how they do it - Producing *just* enough amps to operate the low-power electronics, but the high-draw of a starter... Fuggeddaboutit. Best life I have gotten down here is about 3 years from a normal battery, the optima gave me just over 4 and I thought I was doing great.

Time for a new power brick. The good news: You don't need to spend stupid money on another Optima, just get a comparable size (dimensions) battery from Costco (I think we are group 34R... maybe) in as high an amp output as possible. I stuffed an 850CCA battery into mine, I think that battery would start a 3-day-old dead body. I use my CRD on film sets to run a big inverter, sometimes without the engine running. Even after drawing power for hours, the CRD has never failed to start.

Love me some Costco battery, and the 36 month replacement is the best around. They might have even upped it to 48 month, I don't know. I've never gotten less than a 100% refund when the old ones die. I have them in all my engines.

_________________Proud supporting vendor of LOST JeepsProvider of high quality CRD service in your driveway. Need help? Just ask! I've taken it apart more than most. Email (button below) is preferred to PMOver 70 CRDs currently driving with my timing belt, rockers, or ARP Studs.Just remember: Bad noises = REALLY bad things.